1. Field of the Invention
This invention pertains to means for applying electric power to corona-generating electrodes in an electrostatic precipitator.
2. State of the Prior Art
It has been customary to supply electric power to high-voltage corona-generating electrodes in an electrostatic precipitator from a step-up transformer supported on the roof of the precipitator. Thus, in the prior art, the lead-in conductor coupling the transformer to the high-voltage electrodes extended through the precipitator housing at a position above the high-voltage electrodes.
It was apparent in the prior art that bottom powering of the high-voltage electrodes of an electrostatic precipitator (i.e., locating the transformer at ground level or at the level of a hopper positioned on a platform below the electrodes to collect particulates falling from the electrodes) would simplify installation of the transformer. Bottom powering would also minimize structural loading on the precipitator housing, and would also provide easier access to the transformer and to the interior of the precipitator.
A transformer used to power an industrial electrostatic precipitator typically weighs from 3000 to 5000 pounds, and occupies about 70 cubic feet. Installation of such a transformer at ground level rather than on the roof of the precipitator (typically 50 to 150 feet above ground) would be advantageous in terms of manpower, time and equipment required to accomplish the installation. Furthermore, installation of a transformer at ground level would preclude the need for structural reinforcement of the precipitator housing, which would otherwise be necessary to support the transformer on the precipitator roof.
Access to a transformer for maintenance and repair would be easier, if the transformer were located at ground level rather than on the roof of an electrostatic precipitator. Access to the interior of the precipitator would also be facilitated if the transformer were located at ground level, because entry into a precipitator housing for maintenance purposes is not permitted by the usual safety regulations until visual confirmation has been made that the transformer has been electrically disconnected from the high-voltage electrodes. In accordance with customary safety procedures, keys for unlocking entry doors into the various interior regions of an electrostatic precipitator are kept on a key block located in the vicinity of the transformer in order to facilitate visual verification that the transformer has been disconnected from the high-voltage electrodes before entry into the precipitator housing can be made.
Despite the apparent advantages of bottom powering of an electrostatic precipitator, it was nevertheless deemed necessary in the prior art to locate the transformer at a level above the high-voltage electrodes in order to prevent the lead-in conductor for coupling power from the transformer to the electrodes from becoming coated with particulates removed from the gas stream passing through the precipitator. It was also deemed necessary in the prior art to locate the transformer at a level above the high-voltage electrodes in order to prevent a coating of particulate matter from forming on the insulators that isolate the high-voltage electrodes from electrically grounded components of the precipitator.
Prior to the present invention, no convenient and practicable way had been found for coupling a step-up transformer from a location below the high-voltage electrodes of an electrostatic precipitator to the high-voltage electrodes by means of a lead-in conductor that passes directly from the transformer to the electrodes through the bottom of the precipitator housing.